[Esmaeelef]

Originally Posted by gschaider

When it is ready. Intermediate versions are found in the mercurial-repository. But they may contain bugs so use with care. New features are documented in the README



No. That is the latest released one

Hi Bernhard,

I am using fireFoam solver and trying to define a new field using libswakFunctionObjects.so library. I need to use gravity field for defining the expression, however, I cannot retrieve gravity value to define the expression value. Is there any parameter retrieving gravity vector field?

[wyldckat]

Quick answer: I've moved your post to a new thread, because it was not within the context of the other thread.

I used the following command, executed from within the folder "Examples" in swak4Foam's folder:

find . -name "controlDict" | xargs grep "g"

After scrolling up for a while and checking each line, I spotted something interesting about "getG", inside the file "./groovyBC/fillingTheDam/system/controlDict", namely this:

    getG {
        type executeIfObjectExists;
        readDuringConstruction true;

        objectName g;
        checkType true;
        objectType uniformDimensionedVectorField;
        objectShouldExist false;

        functions {
            loadG {
                type readGravitation;
            }
        }
    }

Oddly enough, I didn't see where it was being used after that...

Either way, there is an example in the README file too, search for "gravity" and you should find an example for including the gravity file "g" and using it directly in the entry for the function object.

[gschaider]

Originally Posted by Esmaeelef

Hi Bernhard,

I am using fireFoam solver and trying to define a new field using libswakFunctionObjects.so library. I need to use gravity field for defining the expression, however, I cannot retrieve gravity value to define the expression value. Is there any parameter retrieving gravity vector field?

Using the actual field is difficult as this is not a regular field. One way would be to read the g-file. This is hidden in the README

**** Macro expansion
     For expressions and variable lists there is now the possibility
     to expand values from the dictionary during reading. The two
     characters that trigger this are
     - $ :: like the regular variable lookup in OpenFOAM.In its most
            complex form it looks like this =$[(type)spec]= where
            =spec= specifies where to look for the value (including
            scoping if the OpenFOAM-version supports it). The optional
            =type= specifies how the entry should be interpreted
     - # :: in variable lists: =#otherList;= includes the variable
            list =otherList= instead of this entry
     These expansions allow the construction of reusable snipplets
     that include information from other parts of the case. For
     instance (this is only part of the specification)
: #include "$FOAM_CASE/constant/g"
: vecName U;
: downComponent (
:     "grav=$[(dimensionedVector)g];"
:     "down=($vecName & grav)/mag(grav);"
: );
: variables (
:     "#downComponent;"
:     "maxDown=max(mag(down));"
: );
     would calculate the component of a vector field that points in
     the direction of the gravity (as specified in the =g=-file).

     This expansion is done during the expression.

[Esmaeelef]

Originally Posted by wyldckat

Quick answer: I've moved your post to a new thread, because it was not within the context of the other thread.

I used the following command, executed from within the folder "Examples" in swak4Foam's folder:

find . -name "controlDict" | xargs grep "g"

After scrolling up for a while and checking each line, I spotted something interesting about "getG", inside the file "./groovyBC/fillingTheDam/system/controlDict", namely this:

    getG {
        type executeIfObjectExists;
        readDuringConstruction true;

        objectName g;
        checkType true;
        objectType uniformDimensionedVectorField;
        objectShouldExist false;

        functions {
            loadG {
                type readGravitation;
            }
        }
    }

Oddly enough, I didn't see where it was being used after that...

Either way, there is an example in the README file too, search for "gravity" and you should find an example for including the gravity file "g" and using it directly in the entry for the function object.

Hi Bruno,
Many thanks for your response. I have another question. In a part of my work, I need to calculate the flow local acceleration DU/Dt (which is in fact du/dt +U.del(U)). To calculate this term, I put (ddt(U)+U&grad(U)) as the expression, However, I get unreasonable results. Do you have any idea if I am on the right track concerning calculation of this term. Thank you in advance

[wyldckat]

Originally Posted by Esmaeelef

I need to calculate the flow local acceleration DU/Dt (which is in fact du/dt +U.del(U)). To calculate this term, I put (ddt(U)+U&grad(U)) as the expression, However, I get unreasonable results.

I'm not familiar enough with the "del" operator, the closest I've dealt with was written on this thread: u.del v notation in openfoam

[gschaider]

Originally Posted by Esmaeelef

Hi Bruno,
Many thanks for your response. I have another question. In a part of my work, I need to calculate the flow local acceleration DU/Dt (which is in fact du/dt +U.del(U)). To calculate this term, I put (ddt(U)+U&grad(U)) as the expression, However, I get unreasonable results. Do you have any idea if I am on the right track concerning calculation of this term. Thank you in advance

Define "unreasonable"